<!DOCTYPE html>
<html lang="en">
<style>
    div {
        width: 100px;
        height: 100px;
        border: 1px solid black;
        background-color: red;
    }
    #fr, #de {
        background-color: blue;
    }
</style>
<div>Red</div>
<div id="fr">Blue</div>
<div id="de">Blue</div>
</html>
